Measurement of antenna parameters by signals from space satellites of the GLONASS and Navstar navigation systems

Antenna systems are widely used in radar, navigation, communication, and radio astronomy. The dimensions of the mirrors of fully rotatable antennas in radio telescopes reach 100 m. The reflector of the variable-profile antenna RATAN-600 is 600 m and that of the “earthen bowl” in Arecibo is 300 m in diameter. A significant number of antennas with mirror diameters 5–20 m, including those having low-end rotary mechanisms with limited rotation velocity and rotation angle, have recently been produced. In preparing antenna systems for regular work after the structure erection or upgrading and mounting of the feed, all of its elements should be tested for compliance of its parameters with design specification, and on-line test for parameter stability is required, especially when working under extreme conditions. The main measured parameters are usually gain or effective area, antenna noise temperature, antenna pattern, combination of electrical and geometric antenna axes (misalignment), and accurate guiding and tracking of the radiation source. Misalignment of the antenna (deviation of the electrical axis from the geometric axis) is caused by the inaccurate design and mounting of the feed or counterreflector, skewness of bearing rods, and mechanical or thermal deformations of the mirror.